1. Field of the Invention
The present invention relates to a center sealing device to be applied to a continuous packaging apparatus for wrapping products by a plastic film substantially in pillow forms. The center sealing device is utilized to seal by heat each cylindrical bag wrapping the product at its center portion, i.e., lapped axial ends thereof.
2. Description of the Prior Art
In a conventional center sealing device applied to such a packaging apparatus, a heat sealing member such as a heating roller is employed for sealing the film by heat. However, since such a heating roller is entirely heated and raises its temperature by an adjacent electric heater, the temperature on its sealing surface tends to vary in portion and in time and cannot be kept uniform depending on the quality and the form of the sealing member and the type and efficiency of the electrical system regarding the electric heater, leading to uneven sealing of the film and to various defects caused by inferior sealing of the film.